U.S. patent number 9,445,919 [Application Number 13/329,845] was granted by the patent office on 2016-09-20 for expandable interbody implant and methods of use.
This patent grant is currently assigned to Warsaw Orthopedic, Inc.. The grantee listed for this patent is William D. Armstrong, Anthony J. Melkent, Keith E. Miller, Stanley T. Palmatier. Invention is credited to William D. Armstrong, Anthony J. Melkent, Keith E. Miller, Stanley T. Palmatier.
United States Patent |
9,445,919 |
Palmatier , et al. |
September 20, 2016 |
**Please see images for:
( Certificate of Correction ) ** |
Expandable interbody implant and methods of use
Abstract
An intervertebral implant is provided. The intervertebral
implant comprises a first component comprising an outer tissue
engaging surface and an inner surface. A second component is
connected to the first component, and is relatively moveable
thereform. The second component comprises an outer tissue engaging
surface and an inner surface. The second component includes an
actuator. A third component is disposed for engagement and is
movable relative to the first and second components. The third
component comprises at least a first ramp and a second ramp axially
spaced apart from the first ramp. The actuator is engageable with
the third component to effect axial translation of the wedge such
that the ramps engage the inner surface of at least one of the
first component and the second component to move the components
between a first, collapsed configuration and a second, expanded
configuration. Methods of use are disclosed.
Inventors: |
Palmatier; Stanley T. (Olive
Branch, MS), Miller; Keith E. (Germantown, TN), Melkent;
Anthony J. (Memphis, TN), Armstrong; William D.
(Memphis, TN) |
Applicant: |
Name |
City |
State |
Country |
Type |
Palmatier; Stanley T.
Miller; Keith E.
Melkent; Anthony J.
Armstrong; William D. |
Olive Branch
Germantown
Memphis
Memphis |
MS
TN
TN
TN |
US
US
US
US |
|
|
Assignee: |
Warsaw Orthopedic, Inc.
(Warsaw, IN)
|
Family
ID: |
48610922 |
Appl.
No.: |
13/329,845 |
Filed: |
December 19, 2011 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20130158664 A1 |
Jun 20, 2013 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F
2/4425 (20130101); A61F 2/447 (20130101); A61F
2002/30062 (20130101); A61F 2002/30492 (20130101); A61F
2002/30593 (20130101); A61F 2002/30601 (20130101); A61F
2310/00221 (20130101); A61F 2002/2817 (20130101); A61F
2002/30469 (20130101); A61F 2002/30878 (20130101); A61F
2002/30538 (20130101); A61F 2002/30774 (20130101); A61F
2/30965 (20130101); A61F 2002/30092 (20130101); A61F
2002/30411 (20130101); A61F 2310/00976 (20130101); A61F
2310/00359 (20130101); A61F 2002/30471 (20130101); A61F
2002/3037 (20130101); A61F 2220/0016 (20130101); A61F
2002/30892 (20130101); A61F 2002/3092 (20130101); A61F
2310/00017 (20130101); A61F 2002/30401 (20130101); A61F
2002/30845 (20130101); A61F 2002/3008 (20130101); A61F
2002/30579 (20130101); A61F 2002/443 (20130101); A61F
2002/30365 (20130101); A61F 2002/30515 (20130101); A61F
2002/30904 (20130101); A61F 2210/0004 (20130101); A61F
2002/30369 (20130101); A61F 2310/00023 (20130101); A61F
2002/30624 (20130101); A61F 2002/30777 (20130101); A61F
2310/00293 (20130101); A61F 2002/304 (20130101); A61F
2002/30433 (20130101); A61F 2002/30331 (20130101); A61F
2310/00029 (20130101); A61F 2310/00341 (20130101); A61F
2310/00179 (20130101); A61F 2002/30622 (20130101); A61F
2002/2835 (20130101); A61F 2002/30166 (20130101); A61F
2002/30405 (20130101); A61F 2002/30448 (20130101); A61F
2002/30785 (20130101); A61F 2002/3093 (20130101); A61F
2002/30507 (20130101); A61F 2002/30556 (20130101); A61F
2002/30677 (20130101); A61F 2002/30266 (20130101); A61F
2002/30357 (20130101) |
Current International
Class: |
A61F
2/44 (20060101); A61F 2/28 (20060101); A61F
2/30 (20060101) |
Field of
Search: |
;623/17.11,17.15,17.16 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Merene; Jan Christopher
Assistant Examiner: Mahmud; Atiya
Claims
What is claimed is:
1. An intervertebral implant comprising: a first component
extending along a longitudinal axis and comprising an outer tissue
engaging surface and an inner surface opposite the outer tissue
engaging surface comprising an inclined portion; a second component
connected to the first component such that the first component is
pivotable relative to the second component about a pin extending
transverse to the longitudinal axis through the first and second
components, the second component comprising an outer tissue
engaging surface and a planar inner surface opposite the outer
tissue engaging surface of the second component extending parallel
to the longitudinal axis, the second component including an
actuator comprising a distal end and an opposite proximal end that
includes a tool socket; and a third component disposed for
engagement and being movable relative to the first and second
components, the third component comprising a planar lower surface
extending parallel to the longitudinal axis and an opposite upper
surface including at least a first ramp and a second ramp axially
spaced apart from the first ramp, wherein the pin is spaced apart
from the third member and the distal end of the actuator comprises
a flange that engages a wall of the third component to retain the
actuator with the third component and effect translation of the
third component in opposite directions along the longitudinal axis
such that the planar lower surface of the third component slidably
engages the planar inner surface of the second component and the
ramps slidably engage the inclined portion to move the components
between a first, collapsed configuration and a second, expanded
configuration.
2. An intervertebral implant as recited in claim 1 wherein the
first ramp has a first height and the second ramp has a second
height, the first height being greater than the second height.
3. An intervertebral implant as recited in claim 1 wherein the
first ramp has a first angle of inclination and the second ramp has
a second angle of inclination, the first angle of inclination being
greater than the second angle of inclination.
4. An intervertebral implant as recited in claim 1 further
comprising a bone graft cavity, wherein at least one of the first,
second and third components define the bone graft cavity, the bone
graft cavity being configured to maintain a bone graft volume
between the first, collapsed configuration and the second, expanded
configuration.
5. An intervertebral implant as recited in claim 1 wherein the
second component includes a wall disposed adjacent a posterior end
thereof, the third component including spaced apart rail portions
extending parallel to the longitudinal axis, wherein opposite ends
of the wall engage inner surfaces of the rail portions during axial
translation, the inner surfaces of the rail portions facing one
another.
6. An intervertebral implant as recited in claim 1 wherein the
third component includes a bone graft receptacle.
7. An intervertebral implant as recited in claim 1 wherein the
third component includes a bone graft receptacle and at least one
of the first and second components include a bone graft
receptacle.
8. An intervertebral implant as recited in claim 1 wherein the
second component includes a wall disposed adjacent a posterior end
thereof, the third component including rail portions that move
within the wall during axial translation.
9. An intervertebral implant as recited in claim 1 wherein the
first, second and third components define a bone graft cavity
defining an axial length, the axial length decreasing as the first,
second and third components move from the first to the second
configuration.
10. An intervertebral implant as recited in claim 1 wherein the
actuator includes a threaded cavity formed in the second component
and a turnbuckle configured for engagement with the third
component.
11. An intervertebral implant as recited in claim 1 wherein the
first ramp comprises an anterior wedge and the second ramp
comprises a posterior wedge such that the anterior wedge is
disposed adjacent an anterior end of the first component and the
posterior wedge is disposed adjacent a posterior end of the first
component.
12. An intervertebral implant as recited in claim 1 wherein the
second expanded configuration includes an initial expansion such
that an anterior end of the implant and a posterior end of the
implant expand equally and a secondary expansion such that the
anterior end of the implant expands greater than the posterior end
of the implant.
13. An intervertebral implant as recited in claim 1 further
comprising a movable linkage attached to an anterior end of the
first component and an anterior end of the third component, wherein
during movement of the components from the second configuration to
the first configuration, the linkage draws the components to a
collapsed orientation.
14. An intervertebral implant as recited in claim 1 wherein the
first ramp is connected with the second ramp via a linear
member.
15. An intervertebral implant as recited in claim 1 wherein: the
inner surface of the first component engages the inner surface of
the second component when the components are in the first,
collapsed configuration; and the inner surface of the first
component is spaced apart from the inner surface of the second
component when the components are in the second, expanded
configuration.
16. An intervertebral implant as recited in claim 1 wherein:
anterior ends of the first and second components directly engage
one another when the components are in the first, collapsed
configuration; and the anterior ends of the first and second
components are spaced apart from one another when the components
are in the second, expanded configuration.
17. An intervertebral implant as recited in claim 1 wherein the
actuator is a threaded screw disposed within a threaded opening of
the second component and comprises a distal end that extends
through an aperture in the third component such that the actuator
is axially fixed relative to the third component.
18. An intervertebral implant as recited in claim 1 wherein the
actuator extends into a first end of the third member without
extending through an opposite second end of the third member.
19. An intervertebral implant comprising: a piston component
comprising an endplate surface and an inner surface disposed in an
opposing orientation relative to the endplate surface, the inner
surface comprising an inclined portion, the piston component
extending along a longitudinal axis between an anterior end and a
posterior end; a base component comprising an endplate surface and
a planar inner surface extending parallel to the longitudinal axis
and disposed in an opposing orientation relative to the endplate
surface of the base component, the base component extending between
an anterior end and a posterior end, the base component being
pivotably connected to the piston component adjacent the respective
posterior ends by a pin extending transverse to the longitudinal
axis through the piston and base components such that the piston
component is rotatable relative to the base component about an axis
of rotation transverse to the longitudinal axis through at least
one plane, the posterior end of the base component including a
threaded cavity; a threaded screw configured for disposal within
the threaded cavity, the threaded screw comprising a distal end and
an opposite proximal end that includes a tool socket; a wedge
disposed for engagement and being movable relative to the piston
and base components, the wedge comprising a planar lower surface
extending parallel to the longitudinal axis and an opposite upper
surface comprising a first ramp having a first height and a first
angle of inclination and a second ramp having a second height and a
second angle of inclination, the first ramp being axially spaced
apart from the second ramp, wherein the distal end of the threaded
screw comprises a flange that engages a wall of the wedge to retain
the threaded screw with the wedge and effect axial translation of
the wedge in opposite directions such that the planar inner surface
of the base component slidably slides along the planar lower
surface of the wedge and the ramps engage the inclined portion of
the piston component to pivot the piston component relative to the
base component such that the components expand between a first,
collapsed configuration and a second, expanded configuration.
20. An intervertebral implant as recited in claim 19 wherein
pivoting the piston component relative to the base component about
the axis of rotation in a first direction causes a distance between
the anterior ends to increase and pivoting the piston component
relative to the base component about the axis of rotation in an
opposite second direction causes a distance between the anterior
ends to decrease.
Description
TECHNICAL FIELD
The present disclosure generally relates to medical devices,
systems and methods for the treatment of musculoskeletal disorders,
and more particularly to an expandable interbody implant system and
method for treating a vertebral column.
BACKGROUND
Spinal disorders such as degenerative disc disease, disc
herniation, osteoporosis, spondylolisthesis, stenosis, scoliosis
and other curvature abnormalities, kyphosis, tumor, and fracture
may result from factors including trauma, disease and degenerative
conditions caused by injury and aging. Spinal disorders typically
result in symptoms including pain, nerve damage, and partial or
complete loss of mobility. For example, after a disc collapse,
severe pain and discomfort can occur due to the pressure exerted on
nerves and the spinal column.
Non-surgical treatments, such as medication, rehabilitation and
exercise can be effective, however, may fail to relieve the
symptoms associated with these disorders. Surgical treatment of
these spinal disorders includes fusion, fixation, discectomy,
laminectomy and implantable prosthetics. These treatments may
employ interbody implants. This disclosure describes an improvement
over these prior art technologies.
SUMMARY
Accordingly, an expandable interbody implant system and method are
disclosed, in one embodiment, an intervertebral implant is
provided. The intervertebral implant comprises a first component
comprising an outer tissue engaging surface and an inner surface. A
second component is connected to the first component, and is
relatively moveable therefrom. The second component comprises an
outer tissue engaging surface and an inner surface. The second
component includes an actuator. A third component is disposed for
engagement and is movable relative to the first and second
components. The third component comprises at least a first ramp and
a second ramp axially spaced apart from the first ramp. The
actuator is engageable with the third component to effect axial
translation of the wedge such that the ramps engage the inner
surface of at least one of the first component and the second
component to move the components between a first, collapsed
configuration and a second, expanded configuration.
In one embodiment, an intervertebral implant comprises a piston
component comprising an endplate surface and an inner surface
disposed in an opposing orientation relative to the endplate
surface. The piston component extends between an anterior end and a
posterior end. A base component comprises an endplate surface and
an inner surface disposed in an opposing orientation relative to
the endplate surface of the base component. The base component
extends between an anterior end and a posterior end. The base
component is pivotably connected to the piston component adjacent
the respective posterior ends. The posterior end of the base
component includes a threaded cavity. A threaded screw is
configured for disposal within the threaded cavity. A wedge is
disposed for engagement and is movable relative to the piston and
base components. The wedge comprises a first ramp having a first
height and a first angle of inclination and a second ramp having a
second height and a second angle of inclination. The first ramp is
axially spaced apart from the second ramp. The threaded screw is
engageable with the wedge to effect axial translation of the wedge
such that the ramps engage the inner surface of the first component
to pivot the first component relative to the second component such
that the components expand between a first, collapsed configuration
and a second, expanded configuration.
In one embodiment, a method for treating a spine is provided. The
method comprises the steps of: providing an intervertebral implant
comprising: a first component having an anterior end and a
posterior end, the first component comprising an outer tissue
engaging surface and an inner surface; a second component having an
anterior end and a posterior end, the second component being
pivotably connected to the first component adjacent the respective
posterior ends, the second component comprising an outer tissue
engaging surface and an inner surface, the second component
including an actuator; and a third component disposed for
engagement and being movable relative to the first and second
components, the third component comprising at least a first ramp
and a second ramp axially spaced apart from the first ramp;
introducing the intervertebral implant in a collapsed configuration
along a substantially posterior approach of a body within an
intervertebral space; and engaging the actuator with the third
component to effect axial translation of the third component
relative to the first and second components such that the ramps
engage the inner surface of at least one of the first component and
the second component to expand the intervertebral implant to a
second, expanded configuration.
BRIEF DESCRIPTION OF THE DRAWINGS
The present disclosure will become more readily apparent from the
specific description accompanied by the following drawings, in
which:
FIG. 1 is a perspective view of one particular embodiment of an
implant of a system in accordance with the principles of the
present disclosure;
FIG. 2 is a perspective view of the implant shown in FIG. 1;
FIG. 3 is a side view of the implant shown in FIG. 1;
FIG. 4 is a side view of the implant shown in FIG. 1;
FIG. 5 is a side cross section view of the implant shown in FIG.
1;
FIG. 6 is a side cross section view of the implant shown in FIG.
1;
FIG. 7 is a perspective view of one embodiment of the components of
the implant shown in FIG. 1;
FIG. 8 is a perspective cutaway view of the implant shown in FIG.
1;
FIG. 9 is a plan view of one embodiment of the implant shown in
FIG. 1;
FIG. 10 is a plan view of the implant shown in FIG. 9;
FIG. 11 is a perspective cutaway view of one embodiment of the
implant shown in FIG. 1;
FIG. 12 is a side view of one embodiment of the implant shown in
FIG. 1;
FIG. 13 is a side view of the implant shown in FIG. 12;
FIG. 14 is a side view of components of a system in accordance with
the principles of the present disclosure disposed with
vertebrae;
FIG. 15 is a side view of components of the system and vertebrae
shown in FIG. 14;
FIG. 16 is a side view of components of the system and vertebrae
shown in FIG. 14;
FIG. 17 is a perspective view of one embodiment of the implant
shown in FIG. 1;
FIG. 18 is a perspective cutaway view of the implant shown in FIG.
17;
FIG. 19 is a perspective view of components of the implant shown in
FIG. 17;
FIG. 20 is a perspective cutaway view of the implant shown in FIG.
17;
FIG. 21 is a perspective cutaway view of the implant shown in FIG.
17;
FIG. 22 is a perspective view of one embodiment of the implant
shown in FIG. 1;
FIG. 23 is a plan view of the implant shown in FIG. 22;
FIG. 24 is a side cross section view of the implant shown in FIG.
22;
FIG. 25 is a side cross section view of the implant shown in FIG.
22;
FIG. 26 is a side cross section view of the implant shown in FIG.
22;
FIG. 27 is a perspective view of one embodiment of the components
of the implant shown in FIG. 22; and
FIG. 28 is a perspective view of a component of the implant shown
in FIG. 22.
DETAILED DESCRIPTION
The exemplary embodiments of an expandable interbody implant system
and related methods of use disclosed herein are discussed in terms
of medical devices for the treatment of musculoskeletal disorders
and more particularly, in terms of an expandable interbody implant
system and related methods for treating a vertebral column. It is
envisioned that the implant system may provide, for example,
fusion, decompression, restoration of sagittal balance and
resistance of subsidence into tissue, such as, for example,
surfaces of vertebral endplates. It is further envisioned that the
system includes an interbody implant that expands after insertion
into an intervertebral disc space and has several features, such
as, for example, facile insertion into the intervertebral disc
space such that less bone removal is necessary during a surgical
procedure, decompression of nerve roots, expansion to restore
sagittal balance such that more expansion is provided on an
anterior side relative to a posterior side in for example a lumbar
application.
In one embodiment, the expandable interbody implant system is
employed with a posterior approach to the intervertebral disc space
such that a distal end of the interbody implant expands more than a
proximal end of the interbody implant to restore lordosis. In one
embodiment, the expandable interbody implant includes a base
component that engages a first vertebral endplate, a piston
component that engages a second vertebral endplate disposed in an
opposing orientation and a double ramp component that is driven
between the base and piston components to drive the base and piston
components apart. It is contemplated that the double ramp component
is moved relative to the base component via a male threaded
component. It is further contemplated that the double ramp includes
two wedges that drive apart the piston and base components at the
proximal and distal ends of the expandable interbody implant. It is
envisioned that the height and angle of each wedge selectively
provides an amount and rate of expansion on each end of the
expandable interbody implant. For example, a steeper and/or taller
wedge on a distal and/or anterior portion of the expandable
interbody implant drives lordosis as the interbody implant is
expanded.
It is envisioned that the expandable interbody implant and methods
of use disclosed herein can be employed to obtain fusion of
vertebrae through a minimally invasive or percutaneous technique.
In one embodiment, the disclosed expandable interbody implant and
methods of use can provide improved spinal treatment with a device
that is made to expand vertically to create lordosis in vertebrae.
It is contemplated that the expandable interbody implant and
methods of use disclosed herein provide a cavity of relatively
large volume for post-packing of at least one agent, for example,
bone graft.
It is envisioned that the present disclosure may be employed to
treat spinal disorders such as, for example, degenerative disc
disease, disc herniation, osteoporosis, spondylolisthesis,
stenosis, scoliosis and other curvature abnormalities, kyphosis,
tumor and fractures. It is contemplated that the present disclosure
may be employed with other osteal and bone related applications,
including those associated with diagnostics and therapeutics. It is
further contemplated that the disclosed expandable interbody
implant may be alternatively employed in a surgical treatment with
a patient in a prone or supine position, and/or employ various
surgical approaches to the spine, including anterior, posterior,
posterior mid-line, medial, lateral, postero-lateral, and/or
antero-lateral approaches, and in other body regions. The
expandable interbody implant of the present disclosure may also be
alternatively employed with procedures for treating the lumbar,
cervical, thoracic and pelvic regions of a spinal column. The
expandable interbody implant and methods of the present disclosure
may also be used on animals, bone models and other non-living
substrates, such as, for example, in training, testing and
demonstration.
The present disclosure may be understood more readily by reference
to the following detailed description of the disclosure taken in
connection with the accompanying drawing figures, which form a part
of this disclosure. It is to be understood that this disclosure is
not limited to the specific devices, methods, conditions or
parameters described and/or shown herein, and that the terminology
used herein is for the purpose of describing particular embodiments
by way of example only and is not intended to be limiting of the
claimed disclosure. Also, as used in the specification and
including the appended claims, the singular forms "a," "an," and
"the" include the plural, and reference to a particular numerical
value includes at least that particular value, unless the context
clearly dictates otherwise. Ranges may be expressed herein as from
"about" or "approximately" one particular value and/or to "about"
or "approximately" another particular value. When such a range is
expressed, another embodiment includes from the one particular
value and/or to the other particular value. Similarly, when values
are expressed as approximations, by use of the antecedent "about,"
it will be understood that the particular value forms another
embodiment. It is also understood that all spatial references, such
as, for example, horizontal, vertical, top, upper, lower, bottom,
outer, inner, terminal (denoting position or location), left and
right, posterior, anterior, and the like, are for illustrative
purposes only and can be varied within the scope of the disclosure.
For example, the references "superior" and "inferior" are relative
and used only in the context to the other, and are not necessarily
"upper" and "lower".
Further, as used in the specification and including the appended
claims, "treating" or "treatment" of a disease or condition refers
to performing a procedure that may include administering one or
more drugs to a patient in an effort to alleviate signs or symptoms
of the disease or condition. Alleviation can occur prior to signs
or symptoms of the disease or condition appearing, as well as after
their appearance. Thus, treating or treatment includes preventing
or prevention of disease or undesirable condition (for example,
preventing the disease from occurring in a patient, who may be
predisposed to the disease but has not yet been diagnosed as having
it). In addition, treating or treatment does not require complete
alleviation of signs or symptoms, does not require a cure, and
specifically includes procedures that have only a marginal effect
on the patient. Treatment can include inhibiting the disease, for
example, arresting its development, or relieving the disease, for
example, causing regression of the disease. For example, treatment
can include reducing acute or chronic inflammation; alleviating
pain and mitigating and inducing re-growth of new ligament, bone
and other tissues; as an adjunct in surgery; and/or any repair
procedure. Also, as used in the specification and including the
appended claims, the term "tissue" includes soft tissue, ligaments,
tendons, cartilage and/or bone unless specifically referred to
otherwise.
The following discussion includes a description of an expandable
interbody implant and related methods of employing the expandable
interbody implant in accordance with the principles of the present
disclosure. Alternate embodiments are also disclosed. Reference
will now be made in detail to the exemplary embodiments of the
present disclosure, which are illustrated in the accompanying
figures. Turning now to FIGS. 1-4, there is illustrated components
of an interbody implant system including an intervertebral implant
40 in accordance with the principles of the present disclosure.
The components of the system can be fabricated from biologically
acceptable materials suitable for medical applications, including
metals, synthetic polymers, ceramics and bone material and/or their
composites, depending on the particular application and/or
preference of a medical practitioner. For example, the components
of the system, individually or collectively, can be fabricated from
materials such as stainless steel alloys, commercially pure
titanium, titanium alloys, Grade 5 titanium, super-elastic titanium
alloys, cobalt-chrome alloys, stainless steel alloys, superelastic
metallic alloys (for example, Nitinol, super elasto-plastic metals,
such as GUM METAL.RTM. manufactured by Toyota Material Incorporated
of Japan), ceramics and composites thereof such as calcium
phosphate (for example, SKELITE.TM. manufactured by Biologix Inc.),
thermoplastics such as polyaryl ether ketone (PAEK) including
polyether ether ketone (PEEK), polyether ketone ketone (PEKK) and
polyetherketone (PEK), carbon-PEEK composites, PEEK-BaSO.sub.4
polymeric rubbers, polyethylene terephthalate (PET), fabric,
silicone, polyurethane, silicone-polyurethane copolymers, polymeric
rubbers, polyolefin rubbers, hydrogels, semi-rigid and rigid
materials, elastomers, rubbers, thermoplastic elastomers, thermoset
elastomers, elastomeric composites, rigid polymers including
polyphenylene, polyamide, polyimide, polyetherimide, polyethylene,
epoxy, bone material including autograft, allograft, xenograft or
transgenic cortical and/or corticocancellous bone, and tissue
growth or differentiation factors, partially resorbable materials,
such as, for example, composites of metals and calcium-based
ceramics, composites of PEEK and calcium based ceramics, composites
of PEEK with resorbable polymers, totally resorbable materials,
such as, for example, calcium based ceramics such as calcium
phosphate, tri-calcium phosphate (TCP), hydroxyapatite (HA)-TCP,
calcium sulfate, or other resorbable polymers such as polylactide,
polyglycolide, polytyrosine carbonate, polycaprolactone and their
combinations. Various components of the system may be fabricated
from material composites, including the above materials, to achieve
various desired characteristics such as strength, rigidity,
elasticity, flexibility, compliance, biomechanical performance,
durability and radiolucency or imaging preference. The components
of the system, individually or collectively, may also be fabricated
from a heterogeneous material such as a combination of two or more
of the above-described materials.
The system including intervertebral implant 40 can be employed as a
stabilization device in fusion and fixation procedures, for
example, for patients suffering from a spinal disorder to provide
height restoration between vertebral bodies, decompression,
restoration of sagittal balance and/or resistance of subsidence
into vertebral endplates. The components of the interbody implant
system may be monolithically formed, integrally connected or
include fastening elements and/or instruments, for example, as
described herein.
Intervertebral implant 40 defines a longitudinal axis a and extends
between a first end, such as, for example, an anterior end 42 and a
second end, such as, for example, a posterior end 44.
Intervertebral implant 40 includes a first component, such as, for
example, a piston component 46 and a second component, such as, for
example, a base component 48 connected to piston component 46. Base
component 48 is movably mounted to piston component 46 with a hinge
50 to facilitate a pivoting connection between components 46, 48.
Components 46, 48 are relatively movable to expand and collapse
with intervertebral implant 40 between a first configuration and a
second configuration, as will be described. It is contemplated that
components 46, 48 may be monolithically formed and/or be connected
via a living hinge. It is further contemplated that base component
48 may be alternatively connected to piston component 42 by
integral connection, press fit, threaded, adhesive and/or fastening
elements such as clips and/or screws. It is envisioned that
intervertebral implant 40 may include one or a plurality of
components.
Piston component 46 includes an outer tissue engaging surface, such
as, for example, an endplate surface 52. Endplate surface 52
defines a substantially rectangular opening 53 extending
therethrough. It is envisioned that opening 53 may be configured
for packing of at least one agent, for example, bone graft. It is
further envisioned that opening 53 may have alternate
configurations, such as, for example, oval, oblong, triangular,
square, polygonal, irregular, uniform, non-uniform, offset,
staggered, undulating, arcuate, variable and/or tapered. It is
contemplated that endplate surface 52 may include one or a
plurality of openings.
Endplate surface 52 is configured to engage an endplate of a
vertebra and includes a plurality of raised elements 54 configured
to enhance fixation and/or gripping with vertebral tissue, Elements
54 are disposed transverse to longitudinal axis a. It is envisioned
that all or only a portion of endplate surface 52 may have
alternate surface configurations to enhance fixation with tissue
such as, for example, rough, arcuate, undulating, mesh, porous,
semi-porous, dimpled and/or textured according to the requirements
of a particular application. It is further envisioned that elements
54 may be disposed at alternate orientations, relative to axis a,
such as, for example, perpendicular and/or other angular
orientations such as acute or obtuse, co-axial and/or may be offset
or staggered.
Piston component 46 includes an inner surface 56 disposed to face
an opposing orientation and/or direction relative to the facing
orientation and/or direction of endplate surface 52. Endplate
surface 52 is oriented in a direction to face tissue of a vertebral
endplate and inner surface 56 is oriented to face an opposite
direction. Inner surface 56 is substantially smooth or even and
configured to engage a surface of a third component, such as, for
example, a wedge 58 such that wedge 58 is movable relative to
components 46, 48.
Piston component 46 includes a first extension 60 and a second
extension 62 extending in a substantially linear configuration
along longitudinal axis a between a first end, such as, for
example, an anterior end 64 and a second end, such as, for example,
a posterior end 66. Extensions 60, 62 are monolithically formed
with ends 64, 66. It is envisioned that extensions 60, 62 may be
alternatively connected to ends 64, 66 by integral connection,
press fit, threaded, adhesive and/or fastening elements such as
hinge, clip and/or screws. Extensions 60, 62 are disposed in a
substantially parallel orientation relative to longitudinal axis a.
It is contemplated that extensions 60 and/or 62 may be disposed at
alternate orientations, relative to longitudinal axis a, for
example, perpendicular, converging, diverging and/or other angular
orientations such as acute or obtuse, co-axial and/or may be offset
or staggered. It is envisioned that extensions 60, 62 may extend in
alternate configurations such as, for example, radius of curvature,
offset and/or staggered. It is further envisioned that extensions
60, 62 may have various cross section configurations, such as, for
example, oval, oblong, triangular, rectangular, square, polygonal,
irregular, uniform, non-uniform, variable, hollow and/or
tapered.
Each of extensions 60, 62 include at least a portion of inner
surface 56 that engages at least a portion of the surface of wedge
58 to expand and collapse intervertebral implant 40 between a first
configuration and a second configuration, as will be described. For
example, each of extensions 60, 62 include a planar portion 68 that
engages base component 48, a first inclined portion 70, a recess
portion 72, a transition 74 and a second inclined portion 76.
Portions 68, 70, 72, 74, 76 are disposed in series along each of
extensions 60, 62. Inclined portions 70, 76 are disposed at an
angle from axis a.
Base component 48 includes an outer tissue engaging surface, such
as, for example, an endplate surface 78. It is envisioned that
endplate surface 78 may include one or a plurality of openings
configured for packing of at least one agent, for example, bone
graft. Endplate surface 78 is configured to engage an endplate of a
vertebra and includes a plurality of raised elements 80 configured
to enhance fixation and/or gripping with vertebral tissue. Elements
80 are disposed transverse to longitudinal axis a. It is envisioned
that all or only a portion of surface 78 may have alternate surface
configurations to enhance fixation with tissue similar to those
alternatives described herein. It is further envisioned that
elements 80 may be disposed at alternate orientations, relative to
longitudinal axis a, similar to those alternatives described
herein.
Base component 48 includes an inner surface 82 disposed to face an
opposing orientation and/or direction relative to the facing
orientation and/or direction of endplate surface 78. Endplate
surface 78 is oriented in a direction to face tissue of a vertebral
endplate and inner surface 82 is oriented to face an opposite
direction. Inner surface 82 is planar and substantially smooth or
even and configured to engage a surface of wedge 58. Inner surface
82 engages the surface of wedge 58 such that wedge 58 is movable
relative to components 46, 48.
Base component 48 extends in a substantially linear configuration
along longitudinal axis a between a first end, such as, for
example, an anterior end 84 and a second end, such as, for example,
a posterior end 86. Posterior end 86 includes a wall 88 that
defines an elongated cavity, such as, for example, threaded opening
90. An actuator, such as, for example, a threaded screw 92 is
configured for disposal within threaded opening 90 and extends to a
distal end 94 that is fixed with wedge 58.
Screw 92 is rotatable relative to wall 88 in a first direction,
such as clockwise, and a second opposing direction, such as counter
clockwise. Screw 92 is configured to mate with threaded opening 90
in a threaded engagement and distal end 94 is fixed with wall 98
and freely rotatable therein. Screw 92 is caused to engage opening
90 and rotated in a selected direction such that screw 92 is
threaded with opening 90. Screw 92 is configured for translation
relative to wall 88 in a first axial direction and a second axial
direction.
Distal end 94 includes a flange 96 that engages a wall 98 of wedge
58 to retain screw 92 with wedge 58, as shown in FIGS. 5 and 6.
Distal end 94 extends through wall 98 and includes a reduced
diameter 100 such that distal end 94 rotates relative to wall 98 to
facilitate axial translation of screw 92 and wedge 58. Reduced
diameter 100 facilitates engagement of an adjacent surface 102 of
screw 92 with wall 98 to drive and axially translate wedge 58, in a
first direction shown by arrow A. Flange 96 engages wall 98 to draw
and axially translate wedge 58, in a second opposing direction
shown by arrow B.
Screw 92 is fixed with wedge 58 to effect axial translation of
wedge 58 such that wedge 58 is movable relative to components 46,
48 to expand and collapse intervertebral implant 40 between a first
configuration and a second configuration, as will be described.
Screw 92 is engaged with an instrument or tool (not shown), to
facilitate actuation of the component parts of intervertebral
implant 40 and disposal thereof in various configurations according
to the requirements of a particular application.
Base component 48 is pivotably connected to piston component 46
adjacent posterior ends 66, 86 with hinge 50 to facilitate a
pivoting connection between components 46, 48. Posterior end 66
includes a pin 104 configured for disposal within an elongated slot
106 of posterior end 86. Pin 104 is movable along an axis
transverse to longitudinal axis a along slot 106 to facilitate
expansion and collapse of intervertebral implant 40 between a first
configuration and a second configuration.
Wedge 58 is disposed in an intermediate orientation with components
46, 48. Wedge 58 includes a first surface 107 that engages
component 46 and a second surface 108 that engages component 48
such that wedge 58 is movable for axial translation relative to
components 46, 48. Wedge 58 includes a first rail portion 110 and a
second rail portion 112, disposed along longitudinal axis a, which
movably engage components 46, 48 to expand and collapse
intervertebral implant 40 between a first configuration and a
second configuration.
Rail portion 110 includes a first ramp, such as, for example, an
anterior wedge portion 114 and a second ramp, such as, for example,
a posterior wedge portion 116. Anterior wedge portion 114 is
axially spaced apart from posterior wedge portion 116 along rail
portion 110. Anterior wedge portion 114 has a first height h1 and a
first angle of inclination .alpha.1 relative to longitudinal axis
a. It is envisioned that height h1 may be in a range of 3-7
millimeters (mm). It is further envisioned that angle .alpha.1 may
be in a range of 30 to 60 degrees.
Posterior wedge portion 116 has a second height h2 and a second
angle of inclination .alpha.2 relative to axis a. It is envisioned
that height h2 may be in a range of 1 to 5 mm. It is envisioned
that angle .alpha.2 may be in a range of 4 to 30 degrees. In one
embodiment, height h1 is greater than height h2. In one embodiment,
angle .alpha.1 is greater than angle .alpha.2.
Rail portion 110 includes a protrusion 118 disposed between wedge
portions 114, 116 such that wedge portions 114, 116 are axially
spaced apart and also connecting wedge portion 114 with wedge
portion 116. Wedge portions 114, 116 and protrusion 118 are
disposed in series along rail portion 110. It is contemplated that
wedge portions 114, 116 drive apart components 46, 48 at anterior
end 42 and posterior end 44 to facilitate expansion and collapse of
intervertebral implant 40 between a first configuration and a
second configuration. It is further contemplated that the height
and/or angle of wedge portions 114, 116 regulates the amount and
rate of expansion of intervertebral implant 40 at least adjacent
rail portion 110. It is envisioned that wedge portions 114, 116 are
monolithically formed, connected by fastening elements or separate
and distinct structure.
Rail portion 112 includes a third ramp, such as, for example, an
anterior wedge portion 120 and a fourth ramp, such as, for example,
a posterior wedge portion 122. Anterior wedge portion 120 is
axially spaced apart from posterior wedge portion 122 along rail
portion 112. Anterior wedge portion 120 has height h1 and angle of
inclination .alpha.1. Posterior wedge portion 122 has height h2 and
angle of inclination .alpha.2.
Rail portion 112 includes a protrusion 124 disposed between wedge
portions 120, 122 such that wedge portions 120, 122 are axially
spaced apart. Protrusion 124 connects wedge portion 120 with wedge
portion 122. Wedge portions 120, 122 and protrusion 124 are
disposed in series along rail portion 112. It is contemplated that
wedge portions 120, 122 drive apart components 46, 48 at anterior
end 42 and posterior end 44 to facilitate expansion and collapse of
intervertebral implant 40 between a first configuration and a
second configuration. It is further contemplated that the height
and/or angle of wedge portions 120, 122 regulates the amount and
rate of expansion of intervertebral implant 40 at least adjacent
rail portion 112. It is envisioned that wedge portions 120, 122 are
monolithically formed, connected by fastening elements or separate
and distinct structure.
Each of rail portions 110, 112 include at least a portion of first
surface 107 that engages at least a portion of inner surface 56 of
component 46 to expand and collapse intervertebral implant 40
between a first configuration and a second configuration. For
example, the portions of surface 107 including wedge portions 114,
116 and protrusion 118 disposed along rail portion 110 slideably
engage portions 68, 70, 72, 74, 76 disposed along extension 60. The
portions of surface 107 including wedge portions 120, 122 and
protrusion 124 disposed along rail portion 112 slideably engage
portions 68, 70, 72, 74, 76 disposed along extension 62. Each of
rail portions 110, 112 also include at least a portion of surface
108 that slidably engages at least a portion of inner surface 82
corresponding to extensions 60, 62.
Rail portions 110, 112 extend in a proximal and/or posterior
direction for disposal about wall 88 adjacent posterior end 44.
Rail portions 110, 112 move about wall 88 during axial translation
of the component parts of intervertebral implant 40.
In one embodiment, as shown in FIGS. 7 and 8, piston component 48
includes a receptacle, such as, for example, a basket 202
configured for disposal of at least one agent, for example, bone
graft. Wedge 58 includes a receptacle, such as, for example, a
basket 204 configured for disposal of at least one agent, for
example, bone graft. In the first, collapsed configuration, baskets
202, 204 are disposed in series in a side by side configuration. As
intervertebral implant 40 is expanded to the second, expanded
configuration, baskets 202, 204 translate to a vertical stacked
configuration such that bone graft can grow through the connected
baskets 202, 204. Each of baskets 202, 204 include a plurality of
openings that allow bone to grow between baskets 202, 204. In one
embodiment, basket 202 is an upper basket having a constant volume
and basket 204 is a lower basket having a constant volume. Baskets
202, 204 are packed with bone graft prior to delivery to a surgical
site and disposed in series in a side by side configuration.
Baskets 202, 204 have ramped interfaces that allows baskets 202,
204 to maintain contact therebetween as intervertebral implant 40
expands from the first, collapsed configuration to the second,
expanded configuration, and baskets 202, 204 transition from a side
by side configuration to a stacked and/or top to bottom
configuration. This interface between baskets 202, 204 has openings
so that bone graft in one of baskets 202, 204 can interface with
bone graft in the other of baskets 202, 204. This configuration
allows bone graft to fuse from a first vertebral endplate through
basket 202 and through basket 204, or vice versa, to a second
vertebral endplate.
In one embodiment, as shown in FIGS. 9 and 10, intervertebral
implant 40 includes a bone graft cavity configured to have a
controlled volume of bone graft disposed with intervertebral
implant 40. Intervertebral implant 40 includes an opening 206
extending through its body and components 46, 48 and 58. Opening
206 is configured for disposal of at least one agent, for example,
bone graft. In the first, collapsed configuration, opening 206
defines a length L1 and cross sectional area such that a volume v
of bone graft is disposed within opening 206. Wall 98 of wedge 58
is disposed in a proximal or posterior position. As intervertebral
implant 40 is expanded to the second, expanded configuration, the
overall height of implant 40 increases and wall 98 is translated
axially in the direction shown by arrow A in FIG. 6, as described
herein. As wall 98 axially translates, the cross-sectional area of
opening 206 is decreased. Wall 98 is translated to a distal or
anterior position such that opening 206 defines a length L2. The
components of intervertebral implant 40 are dimensioned such that a
decrease in length of opening 206 to length L2 and the increase in
height of intervertebral implant 40 are combined to maintain a
substantially constant volume V of bone graft throughout expansion
of intervertebral implant 40. This allows intervertebral implant 40
to maintain a constant volume of bone graft at any height of
expansion. It is contemplated that this configuration for
maintaining hone graft volume avoids the bone graft becoming loose
within opening 206 as intervertebral implant 40 increases in
height. It is further contemplated that tightly packed bone graft
can potentially increase fusion capability. In one embodiment,
intervertebral implant 40 provides a controlled volume of bone
graft such that the components of intervertebral implant 40 are
dimensioned such that a decrease in length of opening 206 to length
L2 occurs at a faster rate than the increase in height of
intervertebral implant 40. As such, the volume of bone graft is
decreased as intervertebral implant 40 expands. This configuration
of intervertebral implant 40 compresses the bone graft as
intervertebral implant 40 is expanded. It is contemplated that the
compressed bone graft within intervertebral implant 40 can increase
the likelihood of fusion to occur from a first vertebral body
through the bone graft into a second vertebral body.
In operation, as shown in FIGS. 3-6, intervertebral implant 40 is
engaged for disposal between a first configuration and a second
configuration such that intervertebral implant 40 expands in an
intervertebral disc space. Intervertebral implant 40 is engaged
with an instrument (not shown) to facilitate actuation of the
component parts of intervertebral implant 40 according to the
requirements of a particular surgical application.
In a first configuration, such as, for example, a collapsed
configuration (FIG. 5), components 46, 48 are disposed in a low
profile orientation with wedge 58 such that planar portions 68 of
extensions 60, 62 are disposed in flush engagement with inner
surface 82. Wedge portions 114, 120 are disposed in flush
engagement with the respective inclined portions 70 of extensions
60, 62 and wedge portions 116, 122 are disposed in engagement with
the respective inclined portions 76 of extensions 60, 62.
Protrusions 118, 124 are disposed within the respective recess
portions 72 of extensions 60, 62.
Upon desired positioning of intervertebral implant 40 according to
the requirements of a particular surgical application, screw 92 is
manipulated to move wedge 58 axially. The instrument engages screw
92 for rotation in a clockwise direction. Screw 92 translates
axially in a first axial direction shown by arrow A. As screw 92
translates axially, surface 102 engages wall 98 to drive wedge 58
axially in the direction shown by arrow A. Wedge portions 114, 120
slidably engage the respective inclined portions 70 of extensions
60, 62 and wedge portions 116, 122 slidably engage the respective
inclined portions 76 of extensions 60, 62. Such slidable engagement
of the surfaces of wedge 58 and components 46, 48, due to the axial
translation of wedge 58, pivots component 46 relative to component
48 in rotation about hinge 50 such that components 46, 48 expand
between the first collapsed configuration and a second, expanded
configuration (FIG. 6). This configuration facilitates expansion of
intervertebral implant 40 such that anterior end 42 has a greater
rate and amount of expansion relative to posterior end 44. It is
contemplated that a steeper and/or taller anterior wedge portion
facilitates lordosis as intervertebral implant 40 is expanded.
In one embodiment, intervertebral implant 40 can be collapsed from
the expanded configuration to an alternate configuration between
the expanded and collapsed configurations, via manipulation of
wedge 58 in a second axial direction, as shown by arrow B in FIG.
6, opposite to the first axial direction. It is envisioned that
reciprocal axial movement of wedge 58 to collapse intervertebral
implant 40 may be desired to reposition or remove intervertebral
implant 40 from a body cavity. Upon disposal of intervertebral
implant 40 in the expanded configuration, to dispose intervertebral
implant 40 in an alternate configuration, screw 92 is rotated in a
counterclockwise direction such that flange 96 engages wall 98 to
draw and axially translate wedge 58, in the second opposing
direction shown by arrow B.
As wedge 58 is translated axially in the second axial direction,
component 46 pivots about hinge 50 to rotate toward the collapsed
configuration such that wedge portions 114, 120 move toward
engagement with the respective inclined portions 70, wedge portions
116, 122 move toward engagement with the respective inclined
portions 76 and protrusions 118, 124 move toward disposal within
the respective recess portions 72. Depending on the application,
components 46, 48 may be returned to the fully collapsed
configuration, as shown in FIG. 5.
In one embodiment, as shown in FIG. 11, an actuator, such as, for
example, a turnbuckle 292 including clockwise threads 294 disposed
at a proximal end 296 and being configured for disposal within
threaded opening 90. Turnbuckle 292 includes counterclockwise
threads 298 disposed at a distal end 300 and being configured for
threaded engagement with wedge 58. Wall 98 defines a threaded
opening 302 configured for disposal of threads 298. From a first
collapsed configuration of intervertebral implant 40 described
above, turnbuckle 292 is manipulated to move wedge 58 axially. The
instrument engages turnbuckle 292 for rotation of threads 294
within threaded opening 90 and rotation of threads 298 within
opening 302 to drive expansion of intervertebral implant 40. As
turnbuckle 292 rotates, the counter rotation of threads 294, 298
causes turnbuckle 292 to drive apart wedge 58 and base component 48
such that wedge 58 translates axially, as described herein. The
surfaces of wedge 58 and components 46, 48 slidably engage as
described above such that components 46, 48 expand between the
first collapsed configuration and a second, expanded
configuration.
In one embodiment, as shown in FIGS. 12 and 13, intervertebral
implant 40 is configured for selective and/or variable expansion
between the first, collapsed configuration and the second, expanded
configuration. It is envisioned that the shape and size of rail
portions 110, 112 of wedge 58 can selectively regulate expansion of
intervertebral implant 40. Wedge portions 114, 120 each include a
first surface 402 having an angle of inclination .beta.1 and a
second surface 404 having an angle of inclination .beta.2. Wedge
portions 116, 122 have an angle of inclination .beta.1. Angle
.beta.2 is greater than angle .beta.1.
Expansion of intervertebral implant 40 between the first and second
configurations includes an initial expansion and a secondary
expansion. Wedge portions 116, 122 and surfaces 402 of wedge
portions 114, 120 have an angle of inclination .beta.1 such that,
during the initial expansion, expansion of intervertebral implant
40 adjacent anterior end 42 and posterior end 44 is substantially
equivalent, as shown by arrows X. It is contemplated that initial
expansion provides decompression of an intervertebral disc space.
After a selected amount of expansion, according to the length of
surface 402, inclined portion 70 of component 46 engages surfaces
404 of wedge portions 114, 120 to override the expansion due to
wedge portions 116, 120. Angle .beta.2 is greater than angle
.beta.1 such that anterior end 42, as shown by arrow Y, expands a
greater amount relative to posterior end 44, as shown by arrow Z.
It is contemplated that the secondary expansion expands an anterior
side of an intervertebral disc space a greater amount relative to a
posterior side to provide lordosis. It is envisioned that other
ramp configurations can be used to expand intervertebral implant 40
in a vertical orientation only, and/or to drive kyphosis in
applications such as the thoracic spine.
In assembly and use, the interbody implant system is employed with
a surgical procedure, such as, a fusion treatment of a spine of a
patient including vertebrae V, intervertebral disc space I and body
areas adjacent thereto, as discussed herein. The interbody implant
system may also be employed with other surgical procedures, such
as, for example, discectomy, laminotomy, laminectomy, nerve root
retraction, foramenotomy, facetectomy, decompression, and spinal,
nucleus or disc replacement.
For example, as shown in FIGS. 14-16, the interbody implant system
can be employed with a surgical arthrodesis procedure, such as, for
example, an interbody fusion for treatment of an applicable
condition or injury of an affected section of a spinal column and
adjacent areas within a body, such as, for example, intervertebral
disc space I between first vertebrae V1 and second vertebrae V2 of
vertebrae V. It is contemplated that intervertebral implant 40 of
the interbody implant system, described above, can be inserted with
intervertebral disc space I to space apart articular joint
surfaces, provide support and maximize stabilization of vertebrae
V. It is further contemplated that intervertebral implant 40
provides height restoration between vertebral bodies,
decompression, restoration of sagittal balance and/or resistance of
subsidence into vertebral endplates.
In use, to treat the affected section of vertebrae V, a medical
practitioner obtains access to a surgical site including vertebrae
V in any appropriate manner, such as through incision and
retraction of tissues. It is envisioned that the interbody implant
system can be used in any existing surgical method or technique
including open surgery, mini-open surgery, minimally invasive
surgery and percutaneous surgical implantation, whereby vertebrae V
is accessed through a mini-incision, or sleeve that provides a
protected passageway to the area. Once access to the surgical site
is obtained, the particular surgical procedure is performed for
treating the spine disorder. Intervertebral implant 40, described
above with regard to FIGS. 1-13, is then employed to augment the
surgical treatment. Intervertebral implant 40 can be delivered or
implanted as a pre-assembled device or can be assembled in situ.
Intervertebral implant 40 can be completely or partially revised,
removed or replaced in situ. It is contemplated that one or all of
the components of the interbody implant system can be delivered to
the surgical site via manual manipulation and/or a free hand
technique. It is further contemplated that intervertebral implant
40 may be inserted posteriorly, and then manipulated anteriorly
and/or lateral and/or medial.
An incision is made in the body of a patient and a cutting
instrument (not shown) creates a surgical pathway P for
implantation of intervertebral implant 40 within the patient body.
A guide instrument (not shown) is employed to initially distract
vertebrae V1 from vertebrae V2, as shown in FIG. 14. A sleeve or
cannula S is used to access intervertebral disc space I and
facilitate delivery and access for components of the interbody
implant system. A preparation instrument (not shown) can be
inserted within the sleeve or cannula and disposed within
intervertebral disc space I. The preparation instrument(s) can be
employed to remove some or all of the disc tissue including the
disc nucleus and fluids, adjacent tissues and/or bone, corticate,
scrape and/or remove tissue from the surfaces of endplates of
opposing vertebrae V1, V2, as well as for aspiration and irrigation
of the region according to the requirements of a particular
surgical application.
As shown in FIG. 15, intervertebral implant 40 is disposed in the
first, collapsed configuration, described above and delivered
through surgical pathway P along a substantially posterior
approach, as shown by arrow C, into intervertebral disc space I
with a delivery instrument (not shown) including a driver. The
driver delivers intervertebral implant 40 into the prepared
intervertebral disc space I, between vertebrae V1 and vertebrae V2,
according to the requirements of a particular surgical
application.
Upon desired positioning of intervertebral implant 40, the driver
or other instrument engages intervertebral implant 40 to facilitate
actuation of the component parts of intervertebral implant 40. The
driver engages screw 92 for rotation in a clockwise direction such
that screw 92 translates axially to drive wedge 58 axially in the
direction shown by arrow D in FIGS. 15 and 16. Wedge portions 114,
120 slidably engage the respective inclined portions 70 of
extensions 60, 62 and wedge portions 116, 122 slidably engage the
respective inclined portions 76 of extensions 60, 62, as shown and
described with regard to FIGS. 5 and 6. Such slidable engagement of
the surfaces of wedge 58 and components 46, 48, due to the axial
translation of wedge 58, pivots component 46 relative to component
48 in rotation about hinge 50 such that components 46, 48 expand
between the first collapsed configuration and a second, expanded
configuration, as shown in FIG. 16. This configuration facilitates
expansion of intervertebral implant 40 such that anterior end 42
has a greater rate and amount of expansion relative to posterior
end 44. It is contemplated that in the expanded configuration,
intervertebral implant 40 provides height restoration between
vertebrae V1 and vertebrae V2, decompression, restoration of
sagittal balance and resistance of subsidence into the endplates of
vertebrae V1 and vertebrae V2.
It is envisioned that the components of the interbody implant
system, which may include one or a plurality of intervertebral
implants 40, can be delivered to the surgical site via alternate
approaches. In one embodiment, intervertebral implant 40 is
delivered through the surgical pathway along a transforaminal
lumbar interbody fusion approach into intervertebral disc space I
and disposed in the expanded configuration. In one embodiment, a
plurality of intervertebral implants 40 are delivered through the
surgical pathway along a posterior lumbar interbody fusion approach
into intervertebral disc space I and disposed in the expanded
configuration in a side by side orientation.
In one embodiment, intervertebral implant 40 can be collapsed from
the expanded configuration to an alternate configurations between
the expanded and collapsed configurations, as described above, to
collapse intervertebral implant 40 as may be desired to reposition
with or remove intervertebral implant 40 from intervertebral disc
space I. In one embodiment, the interbody implant system includes a
plurality of intervertebral implants 40, which can be variously
sized and configured, and/or oriented in a side by side engagement,
spaced apart and/or staggered.
In one embodiment, the interbody implant system includes an agent,
which can include a bone growth promoting material, which may be
disposed, packed or layered within, on or about the components
and/or surfaces of the interbody implant system. The bone growth
promoting material, such as, for example, bone graft can be a
particulate material, which may include an osteoconductive material
such as HA and/or an osteoinductive agent such as a bone
morphogenic protein (BMP) to enhance bony fixation of
intervertebral implant 40 with the adjacent vertebrae V.
It is contemplated that the agent and/or bone graft may include
therapeutic polynucleotides or polypeptides. It is further
contemplated that the agent and/or bone graft may include
biocompatible materials, such as, for example, biocompatible metals
and/or rigid polymers, such as, titanium elements, metal powders of
titanium or titanium compositions, sterile bone materials, such as
allograft or xenograft materials, synthetic bone materials such as
coral and calcium compositions, such as HA, calcium phosphate and
calcium sulfite, biologically active agents, for example, gradual
release compositions such as by blending in a bioresorbable polymer
that releases the biologically active agent or agents in an
appropriate time dependent fashion as the polymer degrades within
the patient. Suitable biologically active agents include, for
example, BMP, Growth and Differentiation Factors proteins (GDF) and
cytokines. Intervertebral implant 40 can be made of radiolucent
materials such as polymers. Radiomarkers may be included for
identification under x-ray, fluoroscopy, CT or other imaging
techniques. It is envisioned that the agent may include one or a
plurality of therapeutic agents and/or pharmacological agents for
release, including sustained release, to treat, for example, pain,
inflammation and degeneration.
In one embodiment, as shown in FIGS. 17-21, the interbody implant
system includes an intervertebral implant 540, similar to
intervertebral implant 40 and its components described above with
regard to FIGS. 1-16. Intervertebral implant 540 defines a
longitudinal axis as and extends between an anterior end 542 and a
posterior end 544. Intervertebral implant 540 includes a piston
component 546 and a base component 548 connected to piston
component 546. Base component 548 is movably mounted to piston
component 546 with a hinge 550 to facilitate a pivoting connection
between components 546, 548. Components 546, 548 are relatively
movable to expand and collapse with intervertebral implant 540
between a first configuration and a second configuration, as will
be described.
Piston component 546 includes an endplate surface 552. Endplate
surface 552 defines a substantially rectangular opening 553.
Endplate surface 552 is configured to engage an endplate of a
vertebra and includes a plurality of raised elements 554 configured
to enhance fixation and/or gripping with vertebral tissue. Elements
554 are disposed transverse to longitudinal axis aa.
Piston component 546 includes an inner surface 556 disposed to face
an opposing orientation and/or direction relative to the facing
orientation and/or direction of endplate surface 552. Endplate
surface 552 is oriented in a direction to face tissue of a
vertebral endplate and inner surface 556 is oriented to face an
opposite direction. Inner surface 556 is substantially smooth or
even and configured to engage a surface of a wedge 558 such that
wedge 558 is movable relative to components 546, 548.
Piston component 546 includes a first extension 560 and a second
extension 562 extending in a substantially linear configuration
along longitudinal axis aa between an anterior end 564 and a
posterior end 566. Extensions 560, 562 are monolithically formed
with ends 564, 566. Extensions 560, 562 are disposed in a
substantially parallel orientation relative to longitudinal axis
aa.
Each of extensions 560, 562 include at least a portion of inner
surface 556 that engages at least a portion of the surface of wedge
558 to expand and collapse intervertebral implant 540 between a
first configuration and a second configuration. Each of extensions
560, 562 include a portion 568 that engages base component 548, an
inclined portion 570 and a linear portion 576. Portions 568, 570,
576 are disposed in series along each of extensions 560, 562.
Inclined portion 570 is disposed at an angle from axis aa.
Base component 548 includes an endplate surface 578. Endplate
surface 578 is configured to engage an endplate of a vertebra and
includes a plurality of raised elements 580 configured to enhance
fixation and/or gripping with vertebral tissue. Elements 580 are
disposed transverse to longitudinal axis aa. Base component 548
includes a wall 582 defining an inner surface configured to support
slidable movement of wedge 558. Wall 582 is disposed on opposing
lateral sides of intervertebral implant 540 such that wedge 558 is
movable within an inner surface boundary of base component 548.
Endplate surface 578 is oriented in a direction to face tissue of a
vertebral endplate and wall 582 is oriented to face wedge 558.
Wedge 558 is movable relative to components 546, 548 within the
inner surface boundary of base 548.
Base component 548 extends in a substantially linear configuration
along longitudinal axis as between an anterior end 584 and a
posterior end 586. Posterior end 586 includes wall portions 588
that supports an actuator, such as, for example, a threaded screw
592. Wall portions 588 fix the position of screw 592 with base
component 548 and facilitate free rotation of screw 592 between
wall portions 588. Screw 592 is configured for disposal between
wall portions 588 and a threaded cavity, such as, for example,
threaded slot 590 defined by a wall 591 of wedge 558.
Screw 592 is rotatable relative to wall portions 588 and wall 591
in a first direction, such as clockwise, and a second opposing
direction, such as counter clockwise. Screw 592 is configured to
mate with threaded slot 590 in a threaded engagement and freely
rotatable therein. Screw 592 is rotated in a clockwise direction
such that engagement with slot 590 axially translates wedge 558, in
a first direction shown by arrow AA in FIGS. 20 and 21. Screw 592
is rotated in a counter clockwise direction such that engagement
with slot 590 axially translates wedge 558, in a second opposing
direction shown by arrow BB.
Screw 592 is fixed with component 548 to effect axial translation
of wedge 558 such that wedge 558 is movable relative to components
546, 548 to expand and collapse intervertebral implant 540 between
a first configuration and a second configuration. Screw 592 is
engaged with an instrument or tool (not shown), to facilitate
actuation of the component parts of intervertebral implant 540 and
disposal thereof in various configurations according to the
requirements of a particular application.
Base component 548 is pivotably connected to piston component 546
adjacent posterior ends 566, 586 with hinge 550 to facilitate a
pivoting connection between components 546, 548. Posterior end 566
includes a pin 604 configured for disposal within an elongated slot
606 of posterior end 586. Pin 604 is movable along an axis
transverse to longitudinal axis as along slot 606 to facilitate
expansion and collapse of intervertebral implant 540 between a
first configuration and a second configuration.
Wedge 558 is disposed in an intermediate orientation with
components 546, 548. Wedge 558 includes a first surface 607 that
engages component 546 and a second surface 608 that engages
component 548 such that wedge 558 is movable for axial translation
relative to components 546, 548. Wedge 558 includes a first rail
portion 610 and a second rail portion 612, disposed along
longitudinal axis aa, which movably engage components 546, 548 to
expand and collapse intervertebral implant 540 between a first
configuration and a second configuration.
Rail portion 610 includes a first ramp, such as, for example, an
anterior wedge portion 614 and a second ramp, such as, for example,
a posterior wedge portion 616. Anterior wedge portion 614 is
axially spaced apart from posterior wedge portion 616 along rail
portion 610. Anterior wedge portion 614 has a height and an angle
of inclination relative to longitudinal axis aa, similar to that
described above. Posterior wedge portion 616 has a height and an
angle of inclination relative to axis aa, similar to that described
above.
Rail portion 610 includes a member 618 disposed between wedge
portions 614, 616 such that wedge portions 614, 616 are axially
spaced apart. Member 618 connects wedge portion 614 with wedge
portion 616. Wedge portions 614, 616 and member 618 are disposed in
series along rail portion 610. It is contemplated that wedge
portions 614, 616 drive apart components 546, 548 at anterior end
542 and posterior end 544 to facilitate expansion and collapse of
intervertebral implant 540 between a first configuration and a
second configuration. It is further contemplated that the height
and/or angle of wedge portions 614, 616 regulates the amount and
rate of expansion of intervertebral implant 540 at least adjacent
rail portion 610. It is envisioned that wedge portions 614, 616 are
monolithically formed, connected by fastening elements or separate
and distinct structure.
Rail portion 612 includes a third ramp, such as, for example, an
anterior wedge portion 620 and a fourth ramp, such as, for example,
a posterior wedge portion 622. Anterior wedge portion 620 is
axially spaced apart from posterior wedge portion 622 along rail
portion 612. Wedge portions 620, 622 each have a height and angle
of inclination, similar to that described above.
Member 618 is disposed between wedge portions 620, 622 such that
wedge portions 620, 622 are axially spaced apart. Member 618
connects wedge portion 620 with wedge portion 622. Wedge portions
620, 622 and member 618 are disposed in series along rail portion
612. It is contemplated that wedge portions 620, 622 drive apart
components 546, 548 at anterior end 542 and posterior end 544 to
facilitate expansion and collapse of intervertebral implant 540
between a first configuration and a second configuration. It is
further contemplated that the height and/or angle of wedge portions
620, 622 regulates the amount and rate of expansion of
intervertebral implant 540 at least adjacent rail portion 612. It
is envisioned that wedge portions 620, 622 are monolithically
formed, connected by fastening elements or separate and distinct
structure.
Each of rail portions 610, 612 include at least a portion of first
surface 607 that engages at least a portion of inner surface 556 of
component 546 to expand and collapse intervertebral implant 540
between a first configuration and a second configuration. The
portions of surface 607 including wedge portions 614, 616 disposed
along rail portion 610 slideably engage portions 570, 576 disposed
along extension 560. The portions of surface 607 including wedge
portions 620, 622 disposed along rail portion 612 slideably engage
portions 570, 576 disposed along extension 562.
Rail portions 610, 612 extend in a proximal and/or posterior
direction for disposal within wall portions 582 adjacent posterior
end 544. Rail portions 610, 612 move within wall portions 582
during axial translation of the component parts of intervertebral
implant 40.
Piston component 548 includes a receptacle, such as, for example, a
basket 702 configured for disposal of at least one agent, for
example, bone graft. Wedge 558 includes a receptacle, such as, for
example, a basket 704 configured for disposal of at least one
agent, for example, bone graft. In the first, collapsed
configuration, baskets 702, 704 are disposed in series in a side by
side configuration. As intervertebral implant 540 is expanded to
the second, expanded configuration, baskets 702, 704 translate to a
vertical stacked configuration such that bone graft can grow
through the connected baskets 702, 704. Each of baskets 702, 704
include a plurality of openings that allow bone to grow between
baskets 702, 704.
In operation, as shown in FIGS. 20 and 21, intervertebral implant
540 is engaged for disposal between a first configuration and a
second configuration such that intervertebral implant 540 expands
in an intervertebral disc space. Intervertebral implant 540 is
engaged with an instrument (not shown) to facilitate actuation of
the component parts of intervertebral implant 540 according to the
requirements of a particular surgical application.
In a first configuration, such as, for example, a collapsed
configuration (FIG. 20), components 546, 548 are disposed in a low
profile orientation with wedge 558. Upon desired positioning of
intervertebral implant 540 according to the requirements of a
particular surgical application, screw 592 is manipulated to move
wedge 558 axially, as described above. As wedge 558 axially
translates in the direction shown by arrow AA, wedge portions 614,
620, 616, 622 slidably engage extensions 560, 562. Such slidable
engagement of the surfaces of wedge 558 and components 546, 548,
due to the axial translation of wedge 558, pivots component 546
relative to component 548 in rotation about hinge 550 such that
components 546, 548 expand between the first collapsed
configuration and a second, expanded configuration (FIG. 21). This
configuration facilitates expansion of intervertebral implant 540
such that anterior end 542 has a greater rate and amount of
expansion relative to posterior end 544.
In one embodiment, intervertebral implant 540 can be collapsed from
the expanded configuration to an alternate configuration between
the expanded and collapsed configurations, via manipulation of
wedge 558 in a second axial direction, as shown by arrow BB in
FIGS. 20 and 21, opposite to the first axial direction. It is
envisioned that reciprocal axial movement of wedge 558 to collapse
intervertebral implant 540 may be desired to reposition or remove
intervertebral implant 540 from a body cavity. Upon disposal of
intervertebral implant 540 in the expanded configuration, to
dispose intervertebral implant 540 in an alternate configuration,
screw 592 is rotated in a counterclockwise direction such that
wedge 558 axially translates, in the second opposing direction
shown by arrow B. As wedge 558 is translated axially in the second
axial direction, component 546 pivots about hinge 550 to rotate
toward the collapsed configuration.
In one embodiment, as shown in FIGS. 22-26, the interbody implant
system includes an intervertebral implant 840, similar to
intervertebral implant 40 and intervertebral implant 540 and their
components described above. Intervertebral implant 840 includes a
base component 848 having a posterior end 886 configured to attach
to an inserter or tool (not shown) that engages a screw 892 for
axially translating a wedge 858. Base component 848 includes a
wedge shaped anterior end 884. Base component 848 protects wedge
858 and screw 892 as intervertebral implant 840 is inserted into an
intervertebral disc space. It is contemplated that forces employed
to introduce or deliver intervertebral implant 840 to the
intervertebral disc space are transmitted through the inserter to
an anterior end 842 of intervertebral implant 840. A piston
component 846 includes an opening 847 and base component 848
includes an opening 849. Openings 847, 849 are configured to
receive radio-opaque markers.
Intervertebral implant 840 includes a linkage component 902 that
connects piston component 846 to wedge 858. Linkage component 902
has a first end 904 including a slot 906 that supports a pin 908 of
piston component 846. Pin 908 is slidably supported with slot 906
for movement therein. Linkage component 902 has a second end 910
connected by a pin 912 with wedge 858.
Linkage component 902 has a passive configuration as intervertebral
implant 840 is expanded to the second, expanded configuration (FIG.
24), as described above with regard to intervertebral implants 40,
540. In applications that require intervertebral implant 840 to be
collapsed, as described herein, the linkage draws piston component
846 into the collapsed configuration (FIG. 26). Linkage component
902 facilitates disposal of intervertebral implant 840 from the
expanded configuration for removal or repositioning of
intervertebral implant 840 in the intervertebral disc space. It is
envisioned that linkage component 902 prevents bone graft and/or
agents from undesirably engaging and/or interfering with wedge 858
during axial translation. Wedge 858 includes openings 859 that
reduce material to reduce medical imaging scatter.
In one embodiment, as shown in FIGS. 27 and 28, intervertebral
implant 840 can be actively collapsed employing a pin and channel
configuration. Piston component 846 includes pins 948 extending
inwardly from extensions 860, 862. Pins 948 are disposed within
channels 950 formed in opposing side walls 952 of wedge 858. Pins
948 are disposed for slidable movement within the configuration of
channels 950. As intervertebral implant 840 is collapsed, as
described herein, wedge 858 is retracted via axial translation.
Channels 950 selectively guide pins along wedge 858 to draw piston
component 846 into the collapsed configuration. It is envisioned
that wedge 858 may include pins and piston component 846 includes
channels for drawing piston component 846 into the collapsed
configuration. It is further envisioned that wedge 858 may include
a dovetail member for slidable movement within channels 950.
It will be understood that various modifications may be made to the
embodiments disclosed herein. Therefore, the above description
should not be construed as limiting, but merely as exemplification
of the various embodiments. Those skilled in the art will envision
other modifications within the scope and spirit of the claims
appended hereto.
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